Apparatus for treating metals or metallic articles



Sept.n 10, 1940. E. s voMEs APPARATUS ron TREATINQ mr/ms` da usTALmc ARTICLES Original Filed Nov. 8, 1934. 2 Sheets-Sheet 1 QHRG mb E l I N VEN TOR A TTORNE Y l0, 1940. H. E. SQMES APPARATUS V1vol: "TREATING lMETALS on METALLIC ARTICLES Sheets-Sheet 2 Original Filed Nov. 8'. 1934 IIE/4 v ml/ENTOR. 4 Howard, 50mg.;

Ary/INVIA.

`A TTORNEY.

Patented Sept. 10, 1940 PATENT OFFICE APPARATUS FOR TREATING METALS R METALLIC ARTICLE S Howard E. Somes, Detroit, Mich.

Original application Novembers, 1934, Serial No.

752,039. Divided and this application November 27, 1937, Serial No. 176,841

13 Claims. (Cl.` 266-7) The-present invention relates to apparatus for treating metals or metallic articles inwhich the phenomenon of electrical heating by induction is utilized in combination with the several features of the invention to eiect various treatments thereof, and is a division of my copending application Serial No. 752,039 for Method of treatingv metlals and metallic articles, filed November 8, 19

It is known that when a piece of metal or a metallic article is passed within the field of an inductionV coil, ya flow of electrical current is induced within said metal or metallic article and causes a heating thereof. The present invention utilizes this phenomenon in yconnection with a suitable treating bath and produces a heating of the metal or metallic article while maintained,

inA a selected treating bath. The invention is particularly though not exclusively adapted for use to effect a cleaning, or degreasing, of the surface of the metal or to eiect the removal of rust in the case of cast iron, scale, corrosion, surface carbon, or the like from the surface thereof. The apparatus also may be used to carry on preparatory. metal treatment processes such, for example, as pickling, case hardening or the like. The apparatus may also be used for operations in coating thel surface of metal or metallic articles with protective coating such as water-Japan, rust-proofing compositions or the like. The apparatus is eilicient in producing the desired results either with usual types of metal stock or with either regularly or irregularly shaped metallic articles.

'I'he invention likewise maybe used in connection with any treatment of metal or metallic articles invwhich it is desired-#to maintain a treating bath at a `predetermined temperature which.

may be different from the temperatureto which the metal or metallic article is to be subjected during the treatment thereof. In this connection the invention may be used with metal treating substances in the bath which volatilize or vaporize at normal temperatures, the presentinvention making it commercially feasible to maintain a sumciently low temperature in the bath to prevent vaporization or gasification thereof.-

this phenomenon is utilized for the first time in combination With selected ingredients of a metal treating bath to achieve new and useful results by heating the metal or metallic article independently of the bath While' immersed therein.

It is a principal object of the present invention to provide an apparatus for treating metal or metallic articles which treatment may be controlled during the entire operation thereof and in which induced electrical currents set up Within the metal or metallic article are utilized to heat the metal or metallic article to be treated While the sam-e is immersed in a bath of suitable ingredients to eiect the desired treatment there- Such bath may be in. the physical form of a liquid, such as various acid or alkaline solutions, coating compositions or the like, or of a solid such as a salt or combination of salts or the like, or in some instances the bath may be maintained as a vapor or a gas.

It is a further object of the present invention to provide apparatus for cleaning the surlface of a metallic article wherein heat due either to hysteresis or eddy currents is utilized to effect a heating of the metal surface while the article is immersed in a suitable cleaning solution. In this connection the invention eiects a thorough mechanical cleaning of the surface of the metallic' article and effects economies therein because of the reduced consumption of time and cleaning substances required 4to effect the desired result.

It is a further object of the present invention to provide a metal treating system in which economies may be effected' by the use of lower concentrations of .the treating solutions than in the -prior methods and in which superior results are obtained While using the same concentrations of such solutions as in prior processes.

It is a further object of the present invention to provide a metal cleaning system in which induced heat due to hysteresis and/or electrical currents set up Within the metal to be treated are employed while the metal is immersed in a treating bath to'effect the desired treatment of the metal and in which high conductivity of the treating bath is not essential, nor is it necessary to provide separate electrical connections to each piece of metal or each article subjected to treatment in the process.

It is a further object of the present invention to provide apparatus for treating metal or metallic articles in which a treating bath may be maintained in a liquid phase and thereafter con-4 verted to a vapor or gaseous phase directly at on the line of Fig. 2 in the direction of the the surface of the metal article to be treated and the mechanical energies thus available are utilized at the surface of the metal to eifect the desired treatment thereof.

Other objects of this invention .will appear, in the following description and appended claims, reference being had to the accompanying drawings form a part of this specification wherein like reference characters designate correspond-- ing parts in the several views;

Processes capable of being performed on the present apparatus form the subject matter of Patent No. 2,118,480, issued on an application applied for November 8, 1934, of which the present application is a division.

Fig. 1 is a fragmentary view, partially in elevation, showing a longitudinal section through I an enclosed conveyor system adapted for use in the present invention, this view showing particularly the initial stage and the construction of the treating tanks.

Fig. 2 is a fragmentary view in longitudinalA section showing a portion of the enclosed conveyor system adapted for use with the present invention and showing the portions thereof adapted for the rinsing and drying of the object being subjected to treatment.

Fig. 3 is a cross section taken substantially on the line 3-3 of Fig. 1 in the direction of the arrows.

Fig. 4 is a cross section taken substantially arrows.

Fig. 5 is a fragmentary top plan View taken substantially on the line 5 5 of Fig. 1 in the nally of the enclosures.

Fig. 6 is an enlarged View taken substantially on the line 6--6 in the direction of the arrows of Fig. 5 showing a trolley for effecting rotation of the article carried thereon while passinglongitudinally of the enclosures.

Fig. 7 is a sectional view taken substantially on the line 'l-l in the direction of the arrows of Fig. 6. f

Fig. 8 is a view similar to Fig. 3 but showing a modified form of construction wherein the induction coils are embedded within the walls of the conveyor enclosure.

The apparatus shown herein consists of a conveyor mechanism of any conventional type such as a single or two strand type, and may be either of the overhead or of the platform type. As here shown the conveyor is of the single strand type having a conveyor track I0 suspended above the trolleys II which are movable relative thereto. 'I'his type of conveyor is known generally as the overhead type. The trolleys II are joined by suitableA connecting members I2 which may be, as here shown, a series of joined links.

The connection may, however, be of any preferred type so long as it is sufiiciently flexible and will effect substantially simultaneous movement of the trolleys II relative to therconveyor track ID. 'I'he trolleys II are connected in such a manner as to form an endless belt and the track I0 is formed with return portions (not shown) so that the trolleys I I may move in a predetermined path thereon and travel about a predetermined cycle. Such a conveyor mechanism may be particularly adapted for treatment use, the trolleys I I as here shown,l causing movement of an article carried thereon in a plurality of directions relative to the.

track I0 so as to expose the article to substantially uniform heating by intersecting the magnetic lines of the induction coils in a plurality of directions While being moved thereof.

In order to treat an article carried on the conveyor a selected portion of the conveyor track is enclosed within an enclosure indicated generally at' I3 which preferably is formed of any nonconducting non-magnetic material such as concrete, glass, wood, rubber, synthetic plastic substances or the like, which, while forming an enclosure for the conveyor system, also forms a tank or receptacle suitable for holding the bath employed in carrying out the process. The enclosure I3 surrounds the entire conveyor system at predetermined points and is in the general form of an enclosed tunnel which conforms -to the rises and falls of the conveyor system. The enclosure I3 preferably comprises an entrance portion I4 and tank portions I5 and I6 separated by dividing walls I'l. AAny number of tank portions may be provided in the system, depending upon the number of baths which are to be employed in carrying out various processes. A spray rinse portion I8 and a heated oven portion I9 may also be provided within other portions of the enclosure and for further treatment.

Surrounding the circumference of the enclosure I3 at the tank portions I5 and I6 are a series of induction heating coils 2| which are electrically connected with a suitable source of high frequency electric current (not shown). The high frequency electric current employed in theinduction heating coils may be the standard 60 cycle current or this may be increased to any desired higher frequency. Where the piece of metal or the metallic articles to be treated are relatively thick, a relatively lower frequency may be used than for metal or metallic articles of thinner.

\ in Fig. 1 or they-may be embedded within the walls of the enclosure I3 as shown in Fig. 8. The coils 2Ia are coiled flat, preferably placed on the outside surfaces of the walls of the enclosure I3. They may, howeverfbe embedded in the walls similarly to the embedding of the coils 2| in the walls as shown in Fig. 8. InA either instance the operation of the coilsis substantially the same although the shape of the coils and their placement in the enclosure I3 will determine the direction of travel of the induced currents. The coils 2I or 2 Ia. preferably area series of independent coils which are separately controlled either as to frequency or current or both from suitable control mechanism (not shown). This provides a varying range of induced heat in the metal or metallic article which passes inside the coils and this may be regulated and graduated in any preferred manner. This construction, therefore, will permit the use of a range of selected temperatures in the metal or metallic article as it passes through selected portions of the present mechanism in carrying out certain process steps.

In general, it will be found that inmany operations, such for` example, as in rust-proofing processes for ferrous metals, a relatively higher frequency or flux or both is preferred at the belongitudinally ginning of the process than in succeeding steps of the process. Also that the higher frequencies are desirable where the maximum controllability of the field is desired.

Where the objects to be treated are of irregular shapes and varying thickness, yit will be found that as a general rule a higher frequency of current is required for the thin articles than where the articles are thicker.

The temperature of the baths within the tanks I and I 6 is controlled by suitable temperature controlling elements 22 which, as here shown, may be heaters of the electrically actuated immersion type of any conventional design and electrically connected with a suitable source of electrical energy (not shown).y In certain uses of the present invention, however, the temperature control elements 22 may be in the nature of cooling coils or the like which in such instance would be operatively connected with suitable refrigerating mechanism to effect the cooling of the bath therein. The purpose of the temperature control element 22 is to effect either a heating or a cooling of the baths 23 and 24 within the tanks I5 and I6 accordingly as may be desired to carry out most efficiently the particular steps of the process using selected ingredients in the baths..

It will thus be seen that the temperature control means for the baths is an important feature of the invention Which permits the selection of ingredients in the treating baths from a wide variety of solvents or the like, many of which can- I not be used in present commercial processes because of the necessity for `accurate temperature control within xed predetermined limits.

The enclosure I3 is provided also with a spray rinse portion I8 formed from a series of pipes 25 joined to form a conduit which extends circumferentially inside the enclosure I3 and surrounds the conveyor mechanism. The pipes 25 are provided with a plurality of jets 26 through which a selected fluid under pressure from a suitable source of supply (not shown) is discharged as a series of sharp needle sprays in a plurality of directions toward an article suspended from the trolleys Il. Thus any substances remaining on the surface of the object .to be treated after passing through the baths,

may be washed fromthe surface thereof.

The enclosure I3 is also provided with a heated zone I9 which acts as a drying oven and which may be heated either by induction coils 2| of the type heretofore described or may be heated by the conventional type of resistance heating,

element 21 as shown in Fig. 2.

The enclosure I3 terminates as at 28 to permit inspection of the articles after passing through the plurality of lsteps of the process and the conveyor system thereafter may travel into any desired enclosure to effect further treatment of the metallic article, such for example as a paint spray booth or dip tank 29.

The track I0 of the conveyor system is prov vided with a plurality Iof rises and falls in the vertical direction as shown in Fig. 1 to cause a ti-ally'horizontal'plane as they pass over these portions of the track. This construction is not essential, but assists treatment. Preferably the curved portions 30 are provided in the track I0 at points adjacent the induction coils 2| so as to cause movement of the trolleys II and the object suspended therefrom in a transverse direction while moving longitudinally of the coils. In certain installations particularly for treating metal or metallic articles of irregular contour or irregular thicknesses, this added transverse movement in the substantially horizontal plane effects desirable results in that it causes the article to intersect substantially all of the lines of the magnetic iiux flowing from the coils 2| and effects substantially uniform heating of all portions thereof.

The construction of the trolleys II is shown in detail in Figs. 6 and 7. As there shown, each trolley II comprises conveyorl track engaging rollers 3| and 32 mounted on the opposed arms of a rigid U-shaped bracket 33. A depending shaft 34 is secured to the bracket 33. Article conveying means such as a hook 35 is pivotally mounted in a bracket 36 which is formed integrally as a part of a larger bracket 31. The bracket 31 is secured to a toothed gear wheel 38 and extends downwardly therefrom. The gear wheel 38 is mounted for rotation on the shaft 34 and is held in a predetermined position thereon by contact with the shoulder 40 on the shaft 34 which prevents sliding of the gear 38 in an upward vertical direction. The gear wheel 3 8 is supported on a bearing 4| which is carried by a washer 32 held in place on the shaft 34 by means of the nut 43 screw threaded thereon.

The conveyors are joined together by means of connecting members I2 which may bein the form shown in Fig. 6. As there shown, the connections may'be in .the form of a plurality -of links 44 having opposed ball-shaped ends 45 joined together by means of members 46 having sockets 41 on the opposed ends thereof. In this construction one of the links 44 contacts with a portion of the trolley II and effects the move ment thereof upon the movement of the connecting members I2.

Rotary movement is imparted to the gear 38 and the article suspended therefrom by means of 'a toothed rack gear 50 which extends at predetermined points longitudinally of the conveyor and -substantially parallel to the conveyor track I8. The rack gear 50 is adapted for contact with the toothed gear 38 on each of the trolleys II and causes the rotation thereof about the shaft 34 as the trolleys are moved longitudinally of the track Ill. The conveyor track I0 may be held in place in the enclosure I3 by any preferred construction, such for example as shown in Fig. 7 wherein the track I0 is secured as by welding or the like to a plate 60 which is bolted or otherwise secured to the top portion brace member 62 which is suspended from the top of the enclosure I3. Thus the rack gear 50 extends Within the enclosure to the ydesired point and is rigidly supported therein. All conveyorl parts are preferably formed of non-magnetic materials such as 18-8 stainless steel, brass or the like or even non-conducting materials such as Bakelite or the like.

The apparatus as herein shown and described may be used for cleaning of the surface of the metallic articles and also in connection with pickling operations as also a process for removing rust from the surfaces of such articles. In other uses of the apparatus, coatings may be applied to a metallic surface, such for example as a rust-proofing coating, Water-Japanning or the like. The apparatus also may be used satisfactorily to effect heat treating or case hardening of the metallic article being passed therethrough.

The common feature of the invention in these various uses is the provision of a treating bath maintainable at a predetermined selected temperature while heating articles therein by means of electrical induction. By Way of example, if it is desired to use the apparatus to apply a rust-proof coating to an article of ferrous metal, the article passes by means of the conveyor system into the tank l in which the bath 23 is made up of suitable solvents or cleaning substances to remove dirt, rust, scale, grease, or other foreign substances from the surface of the article. As the article passes through the bath, which is preferably maintained in its liquid phase, the cleaning solution penetrates the foreign substances on the surface thereof to a slight extent and then as the object passes within the induction coils 2| the object is instantly heated to a higher temperature than the temperature of the bath and the cleaning solution is l after to be readily removed from the article as it passes through the remaining portion of the bath. Where an alkali is used in the cleaning solution it will be found that this intense heating of the article independently of the bath will in effect concentrate the alkali at the surface of the metal and this will effect greater penetration of the alkali into the foreign substance on the surface of the metal. 'Ihe effect heretofore described of the exploding of the particles from the surface of the object creates ebullition within the solution which, as is known, increases the efficiency of the cleaning operation. The rapid movement in the liquid due to the ebullition causes a further washing of the object.

I'he result of the foregoing is that a more rapid and more thorough cleaning of the surface is available than with other apparatus heretofore used. If in the bath 23 substances are used which are injurious to the subsequent rustprooflng operation, the article may pass into a rinse tank I6 in which a bath 2d of any desired rinsing solution is placed. The same action occurs here as the object passes through the tank and through the induction coils as has heretofore been described in connection with the passing of the article through the bath 23 and the -tank l5.

point ready for the' rust-proofing operation, the bath in the tank I6 may be made up of any suitable rust-proong solution, as, for example, a 2% solution of phosphoric acid and manganese dioxide. This solution may be maintained by the temperature maintaining member 22 at a temperature lower than the temperature induced in the metal or metallic article to effect the particular treatment. As the object passes through this bath and within the field of the induction coils 2l the object is instantly heated to the required temperature of reaction to effect the complete rust-proofing thereof.

In other uses of the apparatus the tanks may be filled with various organic solvents, as for example benzene or trichlorethylene, or with d1- lute solutions of cleaning alkalies and water. When used for purposes of metal treating, the baths are prepared in accordance with the results desired from the treatment; for example,

if the metal is t'o be pickled, the standard pickling solutions may be used and the temperatures of these solutions and the temperatures created Within the article undergoing treatment are regulated according to the preferred practice.

The present invention may also be used satisfactorily in applying protective coatings to metal surfaces, such for example as water-Japans -or Japans containing other diluents. In this instance' the water-Japanning solution is placed in the tank I5 and the article, after having been cleaned`4 in' the bath in the' `tank I5, passes into the water-Japanning solution and through the induction coils at a regulated temperature which is maintained during the entire movement of the object throughithe tank. After having passed through the,water-Japanning solution the object-wouldA then pass directly into the drying oven without passing through the spray rinse. The present apparatus is superior to conventional apparatus in Water-Japanning in that it is possible to maintain and control the temperatures during the immersion of the object in the Japanning solution.' thus securing controlled variations of film thickness.

In carrying out heat treating or case hardening or other metal treating processes the object to be treated is immersed in the proper solution at the proper temperatures for a suitable length of time. In nitriding for example, a bath of ammonia vapor could be used. In case hardening the article to be treated can be immersed in a non-metallic container together with the materials commonly used for forming a carbon coat such as charcoal, bone meal or the like. The container is then passed into the eld of the induction coils. All of these factors may be regulated in apparatus of the present invention by controlling the temperature of the baths by means of the temperature control elements 22, the temperatures within the article by control of the current flowing through the induction coils 2l, and by regulating the speed at which the objects pass through the particular treating baths.

From the foregoing it will be seen that the present apparatus provides a means for carrying out various processes for the' treatment of metal objects by means of immersion in baths and creation of a temperature within the metal object different from the temperature of the bath by means of heat resulting from electric currents induced therein. 'This permits the layout of a progressive series of different operations Which will permit the complete control of the operations lboth as to operation and as to final result from the process. These features are known to those skilled in the particular art.

I do not, therefore, desire to limit the present invention to any particular apparatus or arrangement sequence except as claimed hereinafter.

What I claim is:

1. In an apparatus for treating metal articles, the combination of a tank for containing a treating solution, a series of circumferentially extend-y ing electrically actuated induction heating coils arranged about a horizontal axis surrounding said tank, and a horizontally acting conveyor mechanism for said articles and means independent thereof effective to rotate the article while movinglongitudinally of said tank and in the space inside said coils. y

2. In an apparatus for treating metal articles, the combination of a chamber for containing a treating bath, means for producing a high frequency alternating magnetic eld having a substantially horizontal axis in the interior of said chamber, conveyor means for moving individual articles to be treated through said chamber and through the magnetic eld and in a direction substantially parallel with the axis of the field, and means for varying the angular relation be tween the articles and the magnetic field.

3. In an apparatus for treating metal articles, the combination of a tank for containing a treating solution, a series of circumferentially extending electrically actuated induction heating coils arranged about a horizontal axis surrounding said tank, and an article conveyor mechanism and means independent thereof effective to rotate the article while moving longitudinally of and within said tank and in the space inside said coils and comprising a track depending from the top of said tank and extending longitudinally thereof, a carriage mounted thereon and movable relative thereto, a depending article receiving o member carriedthereon, a rotatable gear connected with said article receiving member and adapted to cause rotation thereof, a rack extending along the side of said tank on lines substantially parallel to said track and contacting with said gear whereby a rotary motion is impartedl track.

4. In an apparatus for treating metallic articles, the combination of a tank for containing a treating solution, a series of induction heating coils surrounding the tank and arranged to be separately controlled as to strength and frequency of current, and a conveyor mechanism extending into said coils and arranged to move the articles longitudinally through the tank and substantially parallel to the axis of the coils through the space inside said coils, said conveyor mechanism being constructed of substantially non-magnetic material having poor conductive or insulative qualities.

5. In an apparatus for treating metallic articles, the' combination of atank for containing a treating solution, a series of induction heating coils surrounding the tank, means for separately controlling the energization of each coil as to current strength and frequency, and a conveyor mechanism extending into the coils arranged to move the articles through the tank and substanthe combination of a tank for containing a treating solution, a series of induction heating coils having substantally horizontal axes surrounding said tank, means for moving the articles through the tank into and'out of the treating solution, and means for differentially energizing said coils to effect a more rapid heating of the articlesl in the advance portions of their progression through the treating4 solution.

7. In an apparatus for treating metal articles, the combination of a tank for containing a treating solution, a series of induction heating coils surrounding said tank and adapted to heat said metal articles,v means for moving the articles through the tank into and out of the treating solution and in the general direction of the axis of the heating coils, and means for controlling and maintaining the temperature of the solution independently of the heat imparted by the induction heating coils and independently of atmospheric temperature.

8. In an apparatus for treating metal articles, the combination of a tank for containinga treating solution, a series of aligned induction substantially horizontal heating coils surrounding said tank, means for moving the articles longitudinally through the tank and into and out of the treating solution, and means for directly maintaining a predetermined bath temperature independent of atmospheric temperature.

9. In an apparatus for treating metal articles, the combination of a'tank for containing a treating solution, a series of induction heating coils surrounding said tank, means for moving the articles through the tank into and out of the treating solution and substantially horizontally therethrough and generally in the direction of the axis of the coils, and means for imparting a lateral component of movement to the article during, its

the combination of a plurality of tank elements 'for containing separate treating baths, means for moving an article into and out of said baths in seriatim substantially horizontally therethrough, and means including a coil having an axis substantially parallel with the horizontal movement for inductively heating the article during its horizontal passage through said baths, said moving means being subjected to the inductive heating means but unaffected by said inductive heating means.

11. In an apparatus for treating metal articles, Y

the combination of an elongated enclosed treating chamber containing a plurality` of tank elements for containing separate treating baths, a spray chamber and a drying chamber, means for substantially horizontally moving an article through said tanks and chambers in seriatim, and means including a coil having an axis substantially parallel with the horizontal movement for inductively heating the articles during their horizontal passage through one of said tanks.

12. In an apparatus for treating metal articles, the lcombination of a tank having a closed top covering the central portion for containing a treating solution, a series of circumferentially extending electrically actuated induction `heating coils surrounding the central portion of said tank, and having their axes arranged substantially horizontal, an inlet and an outlet to said tank through the top thereof and spaced by said closed portion, and a conveyor mechanism adapted to move the article downward through the inlet longitudinally of said tank and through the space inside said coils and upwardly through the outlet.

13. In an apparatus for treating metal articles, the combination of a tank for containing a. treating solution, a series of circumferentially extending electrically actuated induction heating coils surrounding said tank, and a conveyor mechmovement of the conveyor mechanism and said 5 conveyor mechanism passing through said coils.

HGWARD E. SOMES. 

